Clean spot detection for FM transmission

ABSTRACT

Methods and apparatuses for quiet spot detection for radio frequency transmission thereon. According to various embodiments, a device may include a local receiver configured to evaluate one or more frequencies of a frequency band to determine a quiet spot frequency, the device further including a local transmitter configured to transmit signals at the quiet spot frequency.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/970,443 (now U.S. Pat. No. 7,953,382), filed on Jan. 7, 2008, whichclaims priority under 35 U.S.C. §119(e) to U.S. Provisional ApplicationNo. 60/883,581, filed on Jan. 5, 2007.

TECHNICAL FIELD

Embodiments of the present invention relate generally to audiotransmitter and receivers, and more particularly, to devices includingboth a transmitter and a receiver.

BACKGROUND

Portable electronic devices, such as digital audio players, mobiletelephones, and the like, have become increasingly popular. Thesedevices generally require a user to hold the device to their ear eitherdirectly or indirectly by way of earphones or a headset. Although thesedevices perform well for a single user, users sometimes find thatamplifying the sound for either multiple listeners or for “hands-free”use is desired.

Radio transmitters transmit audio signals from a device, such as aportable electronic device, to be detected by a remote radio receiver.In general, a transmitter is programmed to be switched between a fewpre-determined channels, the user selecting one of the channels fortransmitting the audio signals. The use of a transmitter may require auser to manually locate the available channels on a radio band todetermine which channel is sufficiently quiet for transmitting the audiosignals. The user generally determines which of the channels is quietsimply by listening directly to the quality of signals on the availablechannels. Once the user has identified a quiet spot, the user may needto switch the transmitter to the selected channel and enable theelectronic device. After starting up or enabling the electronic device,the user then may be able to transmit audio signals from the device tothe remote radio receiver.

In some cases, a quiet spot on a radio band may become non-quiet.Sometimes this may be due to movement of the remote radio receiver,which may cause a quiet spot to become closer to a location of atransmitter of a radio station which broadcasts on the particularfrequency of the selected quiet spot. For example, a user may use atransmitter in a vehicle to play music from a digital audio player.While driving, the music may be interrupted by a radio stationbroadcasting on the same frequency of the quiet spot. This may be due tothe radio station's signal becoming stronger as the user has drivencloser to the source of the radio station's signal. Resultantly, theuser must repeat the process for finding another quiet spot. In somelarger urban areas, the user may encounter extreme difficulties inlocating and/or maintaining a quiet spot. In addition to the possibledangers of requiring the user to repeatedly locate quiet spots whiledriving, frustration may lead the user to forego use of the transmitteraltogether.

SUMMARY OF THE INVENTION

In view of the challenges in the state of the art, embodiments of thepresent invention are directed to methods and apparatuses for quiet spotdetection for radio frequency transmission. More specifically, there isprovided, in accordance with various embodiments of the presentinvention, a local receiver configured to evaluate one or morefrequencies of a frequency band to determine a quiet spot frequency, anda local transmitter configured to transmit signals at the quiet spotfrequency.

In various embodiments, the local receiver may be configured to store anindicator of the quiet spot frequency on a memory device.

In various embodiments, the local receiver may be configured todetermine the quiet spot frequency based at least in part on signalstrengths of the one or more frequencies. In various ones of theseembodiments, the quiet spot frequency may have a signal strength lowerthan one or more other frequencies of the frequency band. In someembodiments, a received signal strength indicator may be configured todetermine the quiet spot frequency according to an IEEE 802.11 standard.

In various embodiments, the local receiver may be configured tore-evaluate the quiet spot frequency to determine if the quiet spotfrequency has become non-quiet. For some of these embodiments, the localreceiver may be configured to re-evaluate the one or more frequencies todetermine another quiet spot frequency if the evaluated quiet spotfrequency is non-quiet. In some embodiments, the local receiver may beconfigured to re-evaluate the quiet spot frequency upon powering up ofthe device.

In various embodiments, the local transmitter may be configured totransmit signals to a remote sound producing arrangement fordemodulation of the signals.

In various embodiments, a control unit may be provided for tuning remotesound producing arrangement to the quiet spot frequency.

In various embodiments, a display may be provided for displaying theindicator of the quiet spot.

There is also provided, in accordance with various embodiments of thepresent invention, a device for quiet spot detection for radio frequencytransmission that may comprise means for evaluating one or morefrequencies of a frequency band to determine a quiet spot frequency; andmeans for transmitting signals at the quiet spot frequency.

In various embodiments, the means for evaluating the one or morefrequencies may comprise means for evaluating the one or morefrequencies based at least in part on signal strengths of the one ormore frequencies. In various embodiments, the quiet spot frequency mayhave a signal strength lower than one or more other frequencies of thefrequency band. In some embodiments, the means for evaluating the one ormore frequencies may comprise means for re-evaluating the quiet spotfrequency to determine if the quiet spot frequency has become non-quiet.In some embodiments, the means for evaluating the one or morefrequencies may comprise a means for re-evaluating the one or morefrequencies to determine another quiet spot frequency if the evaluatedquiet spot frequency is non-quiet.

In various embodiments, the device may be a wireless handheld device ora digital audio player.

A method for quiet spot detection for radio frequency transmission isalso described. According to various embodiments, the method comprisesevaluating one or more frequencies of a frequency band to determine aquiet spot frequency; storing an indicator of the quiet spot frequency;receiving or retrieving the indicator; and using the indicator totransmit signals on the quiet spot frequency.

In various embodiments, the quiet spot frequency may be determined basedat least in part on signal strengths of the one or more frequencies. Thesignal strengths of the one or more frequencies may be determinedaccording to an IEEE 802.11 standard.

In various embodiments, the method may comprise re-evaluating the quietspot frequency to determine if the quiet spot frequency has becomenon-quiet. In various ones of these embodiments, the method may furthercomprise re-evaluating the one or more frequencies to determine anotherquiet spot frequency if the evaluated quiet spot frequency is non-quiet.

Other features that are considered as characteristic for variousembodiments of the present invention are set forth in the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be readily understood by thefollowing detailed description in conjunction with the accompanyingdrawings. To facilitate this description, like reference numeralsdesignate like structural elements. Embodiments of the invention areillustrated by way of example and not by way of limitation in thefigures of the accompanying drawings.

FIG. 1 is a block diagram of a device for quiet spot detection andtransmission, in accordance with various embodiments of the presentinvention.

FIG. 2 is a block diagram of a system incorporating the device of FIG.1, in accordance with various embodiments of the present invention.

FIG. 3 is a block diagram of another embodiment of a device for quietspot detection and transmission, in accordance with various embodimentsof the present invention.

FIG. 4 is a block diagram of another embodiment of a device for quietspot detection and transmission, in accordance with various embodimentsof the present invention.

FIG. 5 is a block diagram of another system including another embodimentof a device for quiet spot detection and transmission, in accordancewith various embodiments of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof wherein like numeralsdesignate like parts throughout, and in which is shown by way ofillustration embodiments in which the invention may be practiced. It isto be understood that other embodiments may be utilized and structuralor logical changes may be made without departing from the scope of thepresent invention. Therefore, the following detailed description is notto be taken in a limiting sense, and the scope of embodiments inaccordance with the present invention is defined by the appended claimsand their equivalents.

The description may use the phrases “in an embodiment,” “inembodiments,” or “in various embodiments,” which may each refer to oneor more of the same or different embodiments. Furthermore, the terms“comprising,” “including,” “having,” and the like, as used with respectto embodiments of the present invention, are synonymous.

The phrase “A/B” means A or B. For the purposes of the presentinvention, the phrase “A and/or B” means “(A), (B), or (A and B).” Forthe purposes of the present invention, the phrase “at least one of A, B,and C” means “(A), (B), (C), (A and B), (A and C), (B and C), or (A, Band C).” For the purposes of the present invention, the phrase “(A)B”means “(B) or (AB),” that is, A is an optional element.

The terms chip, die, integrated circuit, monolithic device,semiconductor device, and microelectronic device are often usedinterchangeably in the microelectronics field. The present invention isapplicable to all of the above as they are generally understood in thefield.

The terms “remote” and “local” as used herein may not necessarily referto locations of the referred-to features but they may, depending on thecontext.

Embodiments of the present invention are directed to methods andapparatuses for quiet spot detection for radio frequency transmission.According to various embodiments, a device may include a receiverconfigured to scan a radio frequency band to detect one or more quietspots; the device can further include a transmitter configured to tunethe device to one of the detected quiet spots. In some embodiments, thedevice may be configured to convert digital data stored on the device toanalog signals, and the analog signals can then be detected by a remotesound producing arrangement such as, for example, a receiver of a remoteradio, television, or other device suitable for the purpose.Accordingly, the disclosed methods and apparatuses may obviate the needfor the user to manually scan the radio frequency band to determine thefrequency of a quiet spot and then manually tune the radio frequencytransmitter to the quiet spot frequency for transmitting data to aremote device.

Illustrated in FIG. 1 is an exemplary embodiment of a device 100 forquiet spot detection for radio frequency transmission. According tovarious embodiments, device 100 may be configured to scan a radiofrequency band to detect one or more quiet spots and transmit signals atone of the detected quiet spots.

Device 100 may comprise a local receiver 110 configured to receive orotherwise detect signals on one or more radio communication frequencies.For example, local receiver 110 may be configured to scan a selected oneor both of the frequency modulation (FM) band and the amplitudemodulation (AM) band. The FM band may, however, be preferred for manyapplications such as, for example, for transmitting music, due thegenerally known fidelity difference between the bands.

As used herein, “quiet spot,” as is generally known in the art, mayrefer to a frequency of a radio frequency band having a signal strengthlower than one or more other frequencies. It is sometimes known in theart to alternatively refer to such a frequency as a “clean spot.”Determining whether a frequency is considered a quiet spot may beachieved using any method suitable for the purpose. For example,according to various embodiments, whether a frequency is considered aquiet spot may be determined based at least in part on a predeterminedthreshold signal strength such that a frequency having a signal strengthbelow the predetermined threshold may be considered a quiet spot. Invarious embodiments, whether a frequency is considered a quiet spot maybe determined based at least in part on relative signal strengths amongtwo or more frequencies such that a frequency may be considered a quietspot if the frequency has a signal strength lower than that of at leastone other frequency. A wide variety of alternate and/or equivalentembodiments or implementations calculated to determine whether afrequency is a quiet spot may be substituted for the embodiments shownand described without departing from the scope of the present invention.

Signal strength may be determined according to any method suitable fordoing so. For example, signal strength may be determined according to anInstitute of Electrical and Electronics Engineers (IEEE) wirelessstandard, e.g., the 802.11-2007 standards along with any revisions,amendments or updates thereto. For example, the proposed 802.11kstandards for Received Signal Strength Indication (RSSI) may be used fordetermining signal strength.

For determining signal strength, device 100 may include a receivedsignal strength indicator (not illustrated) adapted for evaluatingsignal strength of signals detected by local receiver 110. A receivedsignal strength indicator may be formed on the same chip as localreceiver 110, or may be a separate chip of device 100.

Device 100 further comprises a local transmitter 112. Local transmitter112 may be configured to transmit signals at one of the quiet spotsdetected and amplified by local receiver 110. In various embodiments,quiet spots may be detected by a sound producing arrangement (e.g., aremote device such as a receiver of a remote radio, television, or otherdevice suitable for the purpose). According to various embodiments,local receiver 110 and local transmitter 112 may be integrated on asingle chip. Accordingly, the size of device 100 may be minimallyimpacted, if at all, by inclusion of both local transmitter 112 andlocal receiver 110 into device 100. In some applications, however, localreceiver 110 and local transmitter 112 may instead be formed on separatechips and then integrated into device 100.

Illustrated in FIG. 2 is an exemplary system incorporating device 100.As illustrated, signals transmitted by device 100 may be detected by asound producing arrangement including a remote receiver 114 and one ormore speakers 116. Remote receiver 114 may be configured to convert thetransmitted signals into sounds projected by one or more speakers 116.Remote receiver 114 may be any one of such receivers typically found invehicles, but may generally be any remote receiver suitable for thepurpose. For example, remote receiver 114 may be any portable ornon-portable radio receiver. Remote receiver 114 may comprise one ormore of a tuner, a demodulator, and an amplifier for detecting,demodulating, and/or amplifying signals as desired.

Device 100 may be any one of various portable electronic devices. Inaccordance with various embodiments, device 100 may be any deviceconfigured to transmit analog audio signals based at least in part ondigital data stored on a memory device of or otherwise received bydevice 100. For example, device 100 may be an audio player configured totransmit analog audio signals based on digital data stored on a compactdisc or the like.

In accordance with various embodiments, device 100 may be a digitalaudio player. Device 100 may include solid state memory or the like,configured to store digital data representative of some audio recording,which device 100 may then transmit as analog audio signals bearingsubstantial similarity to the recording. For example, digital data maybe a compressed or otherwise encoded digital data file, which whendecompressed or otherwise decoded may be output as analog audio signals.In various ones of these embodiments, the digital data may becompressed/decompressed using any suitable algorithm such as, forexample, a Moving Picture Experts Group (MPEG) standard (e.g., MPEGlayer 3 (MP3)), Advanced Audio Coding (AAC), Windows Media Audio (WMA),Waveform Audio (WAV), and the like.

In accordance with various embodiments, device 100 may be a wirelesshandheld device or the like. A wireless handheld device may be any oneof various mobile devices such as, for example, a mobile telephone, apersonal digital assistant, or a smartphone. In various embodiments,local receiver 110 may receive or otherwise detect signals on one ormore radio communication frequencies to determine a quiet spot, andlocal transmitter 112 may transmit signals of voice, music, or othersounds at the frequency of the quiet spot to remote receiver 114 foramplification by way of one or more speakers 116. For example, device100 may be used in an automobile to allow a user to operate device 100in a hands-free mode by amplifying the received audio signals over theautomobile's speakers. This application may be particularly useful insituations wherein device 100 is not configured to transmit such signalsby way of a personal area network (using the Bluetooth™ specification,for example).

In various embodiments, local receiver 110 may be configured to store atleast one indicator of at least one frequency of the band. The indicatormay be, for example, a particular frequency value (e.g., 94.7 MHz). Invarious embodiments, local receiver 110 may be configured to store anindicator based at least in part on a signal strength at the frequency.So, for example, if local receiver 110 scans the band searching for oneor more quiet spots thereon, local receiver 110 may store, at leasttemporarily, the frequency value(s) of detected quiet spot(s).

As illustrated in FIG. 3, device 100 may include memory 118 or similardata storage means for storing one or more indicators of one or morefrequencies. In these embodiments, local receiver 110 may be configuredto scan at least a portion of the frequency band to locate one or morequiet spots and then transfer to memory 118, or otherwise make availablefor retrieving, indicator(s) of the detected quiet spot(s).

Memory 118 may comprise any data storage device for storing data atleast temporarily. In various embodiments, memory 118 may be the sameelement of device 110 for storing audio data or may be a differentstorage element. Memory 118 may be a volatile memory device or anon-volatile memory device. Memory 118 may be a fully integrated memorydevice or may be a removeable memory device (e.g., a USB flash drive orthe like).

Local transmitter 112 may be configured to receive or retrieve anindicator of at least one frequency of a frequency band. For example,local transmitter 112 may be configured to receive or retrieve theindicator of at least one frequency either directly from local receiver110 or from one or more other components of device 100, such as, forexample, from memory 118. In some embodiments, upon receiving orretrieving an indicator of a frequency, local transmitter 112 maytransmit signals at the received or retrieved frequency. The signalstransmitted by local transmitter 112 may be modulated analog signalscarrying information such as, for example, music or other sound.

In some embodiments, after device 100 has determined a location of aquiet spot, a user may tune device 100 to the frequency of the quietspot. Additionally or alternatively, device 100 may be configured toautomatically tune device 100 to the frequency of the quiet spot. Asused herein, “automatically” may refer to requiring no or limited actionon the part of the user for causing the tuning to occur. So, in theseembodiments, only limited interaction, if any, by the user may berequired for transmitting data from device 100 to a remote device.

The user may be informed of the location of the quiet spot by any methodsuitable for the purpose. For example, as illustrated in FIG. 4, device100 may include a display 120, which may display the frequency of thequiet spot. Display 120 may additionally or alternatively be configuredto display status information such as, for example, information relatingto whether device 100 is scanning a band to determine a quiet spot,storing an indication of a quiet spot, transmitting signals on thefrequency of a quiet spot, or some combination thereof. In variousembodiments, display 120 may be configured to display informationrelated to the audio signals transmitted by device 100 such as, forexample, information related to the music being played (song data,artist data, etc.), information related to the telephone conversationbeing held (telephone number, length of call, etc.), and so forth.

Device 100 may be configured to ensure that a frequency being used atany given time for transmitting audio signals to the remote receiverremains a quiet spot relative to other frequencies of the band. Forthese purposes, in various embodiments, device 100 may be configured todetermine whether the set (or current) quiet spot is still a quiet spotby determining whether any change in the signal strength of the setquiet spot has occurred. Such changes in signal strength may occur, forexample, in situations wherein device 100 is in transit (for example,while the user is driving) or over the course of time as broadcasting onthe band may change.

In various embodiments, device 100 may be configured to periodicallyre-scan at least a portion of the frequency band to determine if anychange in signal strength has occurred. In various embodiments, device100 may be configured to compare the current signal strength against thestored signal strength of previously-scanned frequencies for possiblyjumping to a quieter spot. For example, device 100 may re-evaluate thesignal strength of a detected quiet spot and set it as the new quietspot or keep jumping to another previously-detected quiet spot and so onuntil a quieter spot is found. In other embodiments, device 100 may beconfigured to simply determine whether the signal strength of the setquiet spot has changed rather than scanning multiple frequencies. If achange in the signal strength of the set quiet spot has occurred, device100 may be configured to display a new quiet spot on display 120 and/orretune device 100 to transmit signals at another quiet spot.

Device 100 may be configured such that if device 100 is shut down andthen re-started, device 100 may determine whether an indication of alocation of a quiet spot is already stored on device 100 (such as, forexample, on memory 118 as illustrated in FIG. 3). Accordingly, a usermay avoid having to wait for device 100 to re-scan the radio band tofind a quiet spot if the location of a quiet spot is already known.

According to various embodiments, if a location of a quiet spot is notalready stored on device 100, device 100 may be configured to scan atleast a portion of the radio band to locate one or more quiet spots. Onthe other hand, if an indication of a location of a quiet spot isalready stored on device 100, device 100 may be configured to transmitsignals at a frequency corresponding to the location of the quiet spotstored on device 100. If device 100 is not already tuned to transmitsignals of the stored quiet spot frequency, device 100 may be configuredto tune device 100 to transmit signals at the frequency of the storedquiet spot. In various embodiments, device 100 may be configured todisplay the frequency of the stored quiet spot on display 120.

As illustrated in FIG. 5, device 100 may include a control unit 122configured to automatically tune remote receiver 114 to a frequency of aquiet spot. In some embodiments, control unit 122 may be configured toset remote receiver to the frequency of the quiet spot with no or littleaction required on the part of the user.

In various embodiments, control unit 122 may be configured to enlist theRadio Data System (RDS) standard (sometimes alternately referred to asRadio Broadcast Data System (RBDS) standard) for re-tuning remotereceiver 114 to a different frequency.

In various embodiments, control unit 122 may communicate with, andre-tune, remote receiver 114 over one or more wired and/or wirelessnetworks including, but not limited to, personal area networks, localarea networks, wide area networks, metropolitan area networks, etc.Alternatively, control unit 122 may communicate with, and re-tune,remote receiver 114 over a wired connection such as, for example, auniversal serial bus (USB) connection, FireWire™, or the like. The datatransmission may be done in a manner compatible with any of a number ofstandards and/or specifications including, but not limited to, any oneof the IEEE wireless standards, e.g., the 802.11-2007 standards alongwith any revisions, amendments, or updates thereto, Bluetooth™, GlobalSystem for Mobile Communications (GSM), code-division multiple access(CDMA), Ethernet, etc.

Although certain embodiments have been illustrated and described hereinfor purposes of description of the preferred embodiment, a wide varietyof alternate and/or equivalent embodiments or implementations calculatedto achieve the same purposes may be substituted for the embodimentsshown and described without departing from the scope of the presentinvention. Embodiments in accordance with the present invention may beimplemented in a very wide variety of ways. This application is intendedto cover any adaptations or variations of the embodiments discussedherein.

1. A chip comprising: a receiver configured to evaluate one or morefrequencies of a frequency band to determine a quiet spot frequency; anda transmitter configured to transmit signals at the quiet spotfrequency, wherein the receiver is further configured to evaluate thequiet spot frequency to determine if the quiet spot frequency has becomenon-quiet, and if the quiet spot frequency is determined to benon-quiet, re-evaluate the one or more frequencies to determine anotherquiet spot frequency, wherein based on the receiver determining theanother quiet spot frequency, the transmitter is further configured totransmit signals at the another quiet spot frequency.
 2. The chip ofclaim 1, further comprising memory, wherein the receiver is furtherconfigured to store an indicator of the quiet spot frequency in thememory.
 3. The chip of claim 1, wherein the receiver is configured todetermine the quiet spot frequency based at least in part on a signalstrength of each of the one or more frequencies.
 4. The chip of claim 3,wherein the quiet spot frequency has a signal strength lower than asignal strength corresponding to each of one or more other frequenciesof the frequency band.
 5. The chip of claim 4, further comprising areceived signal strength indicator configured to determine the quietspot frequency according to an IEEE 802.11 standard.
 6. The chip ofclaim 1, wherein the receiver is configured to evaluate the quiet spotfrequency upon powering up the device.
 7. The chip of claim 1, furthercomprising a control unit configured to tune a remote sound producingarrangement to the quiet spot frequency.
 8. The chip of claim 1, whereinthe transmitter is configured to transmit the signals at the quiet spotfrequency to a remote sound producing arrangement for demodulation ofthe signals.
 9. A mobile device comprising the chip of claim
 1. 10. Themobile device of claim 9, further comprising a display configured todisplay an indicator of the quiet spot.
 11. A chip comprising: means forevaluating one or more frequencies of a frequency band to determine aquiet spot frequency; means for transmitting signals at the quiet spotfrequency; means for evaluating the quiet spot frequency to determine ifthe quiet spot frequency has become non-quiet; and means forre-evaluating the one or more frequencies to determine another quietspot frequency, if the evaluated quiet spot frequency is determined tobe non-quiet, wherein the means for transmitting signals is furtherconfigured to transmit signals at the another quiet spot frequency,based on the means for re-evaluating determining the another quiet spotfrequency.
 12. The chip of claim 11, wherein the means for evaluatingthe one or more frequencies comprises means for evaluating the one ormore frequencies based at least in part on a signal strength of each ofthe one or more frequencies.
 13. The chip of claim 12, wherein the quietspot frequency has a signal strength lower than a signal strength ofeach of one or more other frequencies of the frequency band.
 14. Thechip of claim 11, further comprising means for storing an indicator ofthe quiet spot.
 15. The chip of claim 11, further r comprising means totune a remote sound producing arrangement to the quiet spot frequency.16. The chip of claim 11, wherein the means for transmitting signals atthe quiet spot frequency is configured to transmit the signals at thequiet spot frequency to a remote sound producing arrangement fordemodulation of the signals.
 17. A mobile device comprising the chip ofclaim
 11. 18. The mobile device of claim 17, further comprising displaymeans for displaying an indicator of the quiet spot.